年前

• Yet oxygen gas did not begin to accumulate in the atmosphere until about 2 billion years ago .
  但是大约在20亿年前，氧气才开始在大气层中积累。
• Fourscore and seven years ago our fathers brought forth on this continent a new nation .
  八十七年前我们的先辈在这块大陆上建立了一个新的国家。
• He got a lot of publicity at the time--two or three years ago--a money scandal of some kind .
  两三年前，此人曾因一项钱财的舞弊丑闻闹得满城风雨。
• He killed mart wiley, a deputy sheriff, at a lost nation kitchen-dance two years ago .
  两年前他在边陲地区的一次厨房舞会上杀死了副长官马丁威利。
• The young face reminded celia sharply of bruce at the same age, sixteen years ago .
  那张年幼的脸，使西莉亚历历在目地回想起十六年前布鲁斯这么大的时候。
• Until ten years ago eastern religions did not meet with any widespread interest in the united states .
  直到十年前，东方宗教在美国还没有引起广泛的兴趣。
• A few decades ago it was discovered that the rotational velocity of the earth undergoes small variations .
  几十年前，人们发现地球自转的速度有微小的变化。
• The church is now a handsome edifice, most part of which was rebuilt forty or fifty years since .
  这座教堂现在是一幢很考究的、大部分是四五十年前盖过的房子。
• Many years ago the spring induced the natives to select the place for their temporary fortification .
  很多年前，这眼清泉，使得土人们选中这儿作为临时筑堡设防的地方。
• Being a rural district 15 years ago , the city is now throbbing with the pulse of modern industry .
  这个城十五年前还是个农业地区，现在有了现代工业在顺利地活跃着。